Christian Gillin, M.D. was a renowned sleep specialist, professor of psychiatry, and Director of the Mental Health Clinical Research Center at the University of California, San Diego. He was past-president of the Society for Light Treatment and Biological Rhythms, the Sleep Research Society, and the West Coast College of Biological Psychiatry. His seminal research in sleep and mood disorders began at the National Institute of Mental Health where he pioneered studies of the antidepressant effects of sleep deprivation, bright light treatment for depression, immunological relationships to sleep, depression and alcoholism. Neuropharmacology, sleep, and chronobiology were his approaches to understanding brain function and psychological disorders, in the search for better treatments. A wonderful teacher, a curious scientist, an empathic doctor, and a friend to many researchers all over the world, he was an inspiring mentor and leader.